Research & reports

Kyla D. Schulte, Caleb J. Wilson, Anna Tawril, Mary A. Jamieson · Ecosphere · United States (Michigan)

A three-year study across 10 strawberry farms along a rural-urban gradient in Michigan, USA, characterized bee abundance, diversity, and community composition. The study found that urbanization, measured as impervious surface cover, had no consistent effect on overall bee abundance and diversity. While urbanization differentially influenced specific taxa (Halictini positively in year one, Ceratinini negatively in year three), the overall impact was limited, with wild bees, especially native species, being important pollinators in urban agriculture.

Alexandra Zink, Paul J. CaraDonna, Kelly Larsen, Amy M. Iler · Ecosphere · United States (Chicago)

This study investigated how urbanization relates to pollination by growing 240 plants (squash and tomato) across six sites with varying urbanization levels in Chicago, Illinois. For tomatoes, the magnitude of pollen limitation increased with greater impervious surface, indicating more pronounced pollination deficits at highly urbanized sites. For squash, evidence of pollen limitation was found only at the most urban site, with a weak trend of pollen limitation of fruit set (but not seed set) increasing with impervious surface.

Stacy M. Philpott, Azucena Lucatero, Sofie Andrade, Cameron R. Hernandez, Peter Bichier · Insects · United States (California)

This study examined how native plant species richness, garden management, and landscape composition affect the abundance and richness of native and non-native bees, ladybeetles, ants, and ground-foraging spiders in urban community gardens (urban agroecosystems) in California, United States. Native plants — about 10% of species but only about 2.5% of plant cover — had little influence on arthropods overall, with the only significant effect being a negative one on non-native spider richness, likely reflecting native plants' low cover. Garden size increased native and non-native bee abundance and richness and non-native spider richness; floral abundance increased non-native spider abundance and native and non-native spider richness; mulch cover and tree/shrub abundance increased non-native spider richness; and natural habitat cover increased non-native bee and native ant abundance but was associated with fewer native ladybeetle species. The study concludes that native plant richness does not strongly influence the abundance and richness of beneficial arthropods.

Kyla D. Scherr, Mary A. Jamieson · Basic and Applied Ecology · United States (Michigan)

This three-year study investigated environmental factors influencing strawberry productivity for two cultivars at ten farms across a rural-urban gradient in Michigan, USA. It found no direct effect of urbanization on strawberry production or fruit pathogen and pest damage, but temperature significantly influenced crop productivity, with cooler rural and warmer urban temperatures limiting fruit number. While no relationship was found between urbanization and overall arthropod pest, predator, or pollinator abundances, Vespidae abundance was positively associated with urbanization, and Araneae abundance was negatively associated.

Mirella Cultrera, Maria Christina de Mello Amorozo, Fábio Cop Ferreira · SITIENTIBUS série Ciências Biológicas · Brazil (Mato Grosso)

An ethnobotanical study in five peripheral neighborhoods of Santo Antônio do Leverger, Mato Grosso, Brazil, surveyed 135 households and detailed 30 to characterize food plant cultivation. Ninety-seven species from 38 families were identified across homegardens, fields, and empty lots. While some species were common, the similarity between species/varieties across households was generally below 50%, and many had low frequency, revealing a vulnerability to species loss despite social network circulation.

Kevin C. Matteson, Gail Langellotto · Insect Conservation and Diversity · United States (New York City)

The ability of adding 70 plants of seven native wildflower species over two years to augment beneficial insect richness, including bees, butterflies, and predatory wasps, was assessed in New York City community gardens. Bayesian analyses failed to find a strong influence of the native plant additions on beneficial insect richness, even after correcting for prior floral abundance. Butterflies and megachilid bees were found to heavily utilize introduced ornamental and crop flowers in these gardens, even when native flowers were present.

Charles Rowley · eScholarship (California Digital Library) · United States (California)

This paper compared the successes and failures of two urban creek restoration programs in California: Temescal Creek (initiated nearly 30 years ago) and White Oak Creek (completed about four years ago). Based on the author's success criteria, the more recent White Oak Creek program achieved significant success, while the earlier Temescal Creek restoration did not reach generally acceptable success levels. This difference is attributed to changes in management and scientific practice over 30 years, including substantial changes in the legal basis for restoration, improved monitoring requirements, and the critical role of properly engineered low flow distribution structures.